The knowledge obtained by observing natural events and conditions in order to discover facts and formulate laws or principles that can be verified or tested

Technology

The application of science for practical purposes

Scientific Law

A summary of many experimental results and observations; a law tells how things work

Scientific Theory

An explanation for some phenomenon that is based on observation, experimentation, and reasoning

Critical Thinking

The ability and willingness to assess claims critically and to make judgements on the basis of objective and supported reasons

Scientific Method

OHEC Used go solve problems

Variables

A factor that changes in an experiment in order to test a hypothesis

Length

A measure of the straight-line distance between two points

Mass

A measure of the amount of matter in an object

Volume

A measure of the size of a body or region in 3 - dimensional space

Weight

A measure of the gravitational force exerted on an object

Scientific Notation

A method of expressing a quantity as a number multiplied by 10 to the appropriate power

Precision

The exactness of the measurement

Significant Figures

A prescribed decimal place that determines the amount of rounding off to be done based on the precision of measurement

Accuracy

A description of how close a measurement is to the true value of the quantity measured

Chemistry

The scientific study of the composition, structure, and properties of matter and the changes that matter undergoes

Matter

Anything that has mass and takes up space

Element

A substance that cannot be separated or broken down into simpler substances by chemical means

Atom

The smallest unit of an element that maintains the properties of that element

Compound

Is substance made of two or more different elements that are chemically combined

Molecule

the smallest unit of a substance that keeps all the physical and chemical properties of that substance

Chemical Formula

A combination of chemical symbols and numbers to represent a substance

Pure Substance

A sample of matter, either a single element or a single compound, that has definite chemical and physical properties

Matter that has a fixed composition and definite properties

Mixture

The combination of two or more substances that are not chemically combined

Heterogeneous Mixture

A mixture where the substances are not mixed uniformly and are not evenly distributed

Homogenous Mixture

A mixture with substances that are mixed uniformly and evenly distributed

Melting Point

The temperature and pressure at which is solid becomes a liquid

Boiling Point

The temperature at which a liquid becomes gas

Density

The ratio of the mass of a substance to the volume of a substance

Reactivity

The ability of a substance to combine chemically with another substance

Flammability

The ability of a substance to react in the presence of oxygen and burn when exposed to flame

Physical Change

A change of matter from one form to another without a change in chemical properties

Chemical Change

A change that occurs when a substance changes composition by forming one or more new substances

Plasma

A state of matter that starts as a gas and then becomes ionized

Energy

The capacity to do work

Thermal energy

The kinetic energy of a substance's atoms

Evaporation

The change of a substance from a liquid to a gas

Sublimation

The process in which a solid changes directly into a gas (sometimes used for reverse process)

Condensation

The change of a substance from a gas to liquid

Fluid

A non solid state of matter in which the atoms or molecules are free to move past each other, examples include a gas or liquid

Buoyant force

The upward force exerted on an object immersed in or floating on a fluid

Pressure

Amount of force exerted per unit area of a surface

Archimedes' Principle

The principle that states the buoyant force on an object in the fluid is an upward force equal to the weight of the volume of fluid that the object displaces

Pascal

The SI unit of pressure, equal to the force of 1 N exerted over an area of 1 m² (abbreviation, Pa)

Pascal's principle

Principle that states that a fluid in equilibrium contained in a vessel in search of pressure of equal intensity in all directions sensible that states that a fluid in equilibrium contained in a vessel in search of pressure off in clinton city in all directions

Viscosity

The resistance of a gas or liquid to flow

Boyle's Law

For a fixed amount of gas at constant temperature, the volume of a gas increases as the pressure of the gas decreases and vice versa

Charles' Law

For a fixed amount of gas at a constant pressure, the volume of the gas increases as the temperature of the gas increases and vice versa

Gay-Lussac's Law

If the pressure of the gas increases as the temperature increases if the volume of a gas does not change

Nucleus

An atom's central region which is made up of protons and neutrons

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

Orbital

A region in an atom where there is a high probability of finding electrons

Valence electron

An electron that is found in the outermost shell of an atom and that determines the atoms chemical properties

Periodic Law

When elements are arranged this way, similarities in their properties will occur in a regular pattern

Period

A horizontal row of elements in the periodic table

Group/Family

A vertical column of elements in the periodic table

Ion

An atom or group of atoms that has a lost or gained one or more electrons and has a negative or positive charge

Atomic number

The number of protons in the nucleus of an atom

Mass number

The sum of the numbers of protons and neutrons in the nucleas of an atom

Isotopes

An atom that has the same number of protons as other atoms of the same element do, but that has a different number of neutrons

Atomic mass unit

Unit of mass that describes the mass of an atom or molecule, it is exactly one- twelfth of the mass of a carbon atom with mass number 12

Average atomic mass

The weighted average of the masses of all naturally occurring isotopes of the element

Metals

Element that is shiny and conducts heat and electricity well

Nonmetal

Element the conducts heat and electricity poorly

Semiconductor

An element or compound that conducts electric current better than an insulator but not as well as a conductor

Alkali Metals

An Element of Group 1

Soft

Shiny

Reacts violently with water

Alkaline-Earth Metals

Element in group 2

Reactive but not as much as Alkali

Transition metal

Element of Groups 3-12

Not as reactive

Halogens

Element of group 17

Reactive

Noble gases

Unreactive element of group 18

Mole

The SI base unit used to measure the amount of a substance whose number of particles is the same as the number of atoms of carbon in 12 g of carbon - 12

Avogadro's Constant

Equals 6.022 ✖ 10²³/ mol ; The number of particles in 1 mol

Molar mass

Mass in grams of one mole of a substance

Chemical Bond

The attractive force that holds atoms together

Chemical Structure

Arrangement of atoms in a substance

Bond Length

Average distance between two nuclei of two bonded atoms

Bond Angle

Angle formed by two bonds to the same atom

Ionic Bond

Bond formed by oppositely charged ions

Conducts electricity in water

Metallic Bonds

A bond formed by the attraction between positively charged metal ions and the electrons around them

Covalent Bonds

Bond formed when atoms share one or more pairs of electrons, they are often formed between non metal atoms

Polyatomic Ions

An ion made of two or more atoms

Empirical Formula

Composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio